Not sexps, but better.
Quite a while back I have read about a system based on Scheme , called termite (I don't remember which scheme that was) that can actually sling live running code/closures across network and execute them remotely..
Boggles my mind even today.
Probably this?
“Concurrency Oriented Programming in Termite Scheme”: http://scheme2006.cs.uchicago.edu/09-germain.pdf
Implemented in Gambit Scheme: https://github.com/FredericHamel/termite-scheme
Erlang also has this capability built in. You can do all kinds of weird stuff with it, it’s great.